eo/src/eoRnd.h

@@ -0,0 +1,97 @@
+// -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
+
+//-----------------------------------------------------------------------------
+// eoRnd.h
+// (c) GeNeura Team, 1998
+//-----------------------------------------------------------------------------
+
+#ifndef _EORND_H
+#define _EORND_H
+
+//-----------------------------------------------------------------------------
+
+#include <eoObject.h>
+
+//-----------------------------------------------------------------------------
+// Class eoRnd
+//-----------------------------------------------------------------------------
+
+#include <stdlib.h>   // srand
+#include <time.h>     // time
+#include <stdexcept>  // runtime_error
+
+//-----------------------------------------------------------------------------
+
+#include <eoPersistent.h>
+
+//-----------------------------------------------------------------------------
+/** 
+ * Base class for a family of random number generators. Generates numbers 
+ * according to the parameters given in the constructor. Uses the machine's 
+ * own random number generators. Which is not too good, after all. 
+ */
+template<class T>
+class eoRnd: public eoObject, public eoPersistent
+{
+public:
+
+  /// default constructor
+  eoRnd(unsigned _seed = 0) { 
+    if ( !started ) {
+      srand(_seed?_seed:time(0));
+      started = true;
+    }
+  }
+    
+  /// Copy cotor
+  eoRnd(const eoRnd& _r ) {srand(time(0));};
+
+  /** Main function: random generators act as functors, that return random numbers. 
+	It´s non-const because it might modify a seed
+	@return return a random number
+	*/
+  virtual T operator()() = 0;
+  
+  /** Return the class id. 
+  @return the class name as a string
+  */
+  virtual string className() const { return "eoRandom"; };
+
+  /**
+   * Read object.
+   * @param is A istream.
+   * @throw runtime_exception If a valid object can't be read.
+   */
+  virtual void readFrom(istream& _is);
+  
+  /**
+   * print object. Prints just the ID, since the seed is not accesible.
+   * @param is A ostream.
+   */
+  void printOn(ostream& _os) const { _os << endl; };
+
+private:
+	/// true if the RNG has been started already. If it starts every time, means trouble.
+	static bool started;
+};
+
+template<class T> bool eoRnd<T>::started = false;
+
+
+//--------------------------------------------------------------------------
+
+/**
+ * Read object.
+ * @param is A istream.
+ * @throw runtime_exception If a valid object can't be read.
+ */
+template<class T>
+void eoRnd<T>::readFrom(istream& _is) {
+  if (!_is)   
+    throw runtime_error("Problems reading from stream in eoRnd");
+  long seed;
+  _is >> seed;
+  srand(seed);
+}
+
+#endif